RS-232 to RS-485 Serial Communications Adapter

30020

$35.00

USD

Qty
Price
1
$35.00 ea.

RS-232 to RS-485 - sometimes you need the flexibility that a RS-485 gives you over the simple RS232!


Description [Hide]

Power Requirements
  Requires at least two RS-232 output handshake lines for power.
RS-232 Side
Connector: DB-9 female
Signals: Passes through pins 3 (TD) and 2 (RD). Pins 7 (RTS) and 8 (CTS) are tied together. Pins 4 (DTR), 6 (DSR), and 1 (CD) are tied together.
RS-485 Side
Connector: 3 pin terminal block
Signals: Half-duplex two-wire operation only. Automatic control circuit enables driver only when transmitting. Receiver is disabled when transmitting to prevent echo back to RS-232 device. Can transmit up to 4000 feet at 19,200 baud.
Dimensions
  2.75" x 1.25" x 0.6"
7cm x 3.2cm x 1.5cm
 
No handshaking is required to control the RS-485 driver. The handshake lines are required but only to provide power to the converter. The RS-485 driver is automatically enabled during each spacing state on the RS-232 side. During the marking or idle state, the RS-485 driver is disabled and the data lines are held in the marking state by pull-up and pull-down resistors.

The SCA-321 has an internal connection to prevent data transmitted from the RS-232 port from being echoed back to the RS-232 port. The SCA-321 is used as a two wire (half duplex) RS-485 converter with a third conductor to be used as signal ground. Using a common signal ground ensures that the common mode voltage between devices falls within the specifications of RS-485. This is especially important for networked devices with opto-isolated RS-485 interfaces.

Using the SCA-321 to communicate to most RS-485 devices does not usually require any termination. Termination is used to match impedance of a node to the impedance of the transmission line being used. When impedances are mismatched, the transmitted signal is not completely absorbed by the load and a portion is reflected back into the transmission line. This reflected signal can cause communication errors especially on long cable runs using a high data rate. If termination is required, the SCA-321 only supports AC coupled terminators. One terminator should be installed on each end of a straight cable run. A typical AC termination is a 120 Ohm resistor and a 0.1 uF capacitor in series between 485(+) and 485(-).

Documentation [Hide]

You Might Also Like [Hide]

50572

SparkFun USB to RS-485 Converter

This breakout board pairs an SP3485 RS-485 transceiver with an FT232RL USB UART IC to convert a USB stream to RS-485.

$19.95 USD



50450

Arduino USB Board (Uno R3)

The Arduino Uno is the all-new replacement for the favourite and popular Arduino Duemilanove. Now shipping R3!

$29.45 USD



27280

EFX-Tek RS-485 Adapter

The EFX-Tek RS-485 adapter is an ideal solution for putting multiple microcontrollers on a custom network.

$31.46 USD



50550

Logic Level Converter

The SparkFun logic level converter is a small device that safely steps down 5V signals to 3.3V and steps up 3.3V to 5V. This level converter also works with 2.8V and 1.8V devices.

$1.95 USD



21197

Parallax USB to Serial RS-232 Adapter

The Parallax USB to RS-232 is a great little adapter that takes your mini-USB connector and converts it to a RS-232 interface!

$14.95 USD



23140

Pololu 3/8" Metal Ball Caster

This Pololu caster uses a 3/8" metal ball to give a nice, low-friction ride at a height of 0.4" to 0.6"

$2.99 USD



29074

Grove - Touch Sensor

It's a ready-to-use touch sensor switch compatible with the Grove system. Plug it in, tuck it in behind a non-metallic surface, and you are finished.

$4.20 USD



52660

OpenBeam Shaft Clamp Kit

The OpenBeam Shaft Clamp Kit allows you to clamp shafts anywhere on your OpenBeam project.

$8.00 USD



52822

PCBGrip Tri Nut Accessory (pairs)

Inserting and aligning nuts into Openbeam can be a bit tricky, but this clever, simple tri-nut insert is a simple, effective solution to the problem.

$4.60 USD



33230

Parallax RFID - 50mm Round Tag

This 50mm Round Tag is a 125 kHz RFID Tag.

$1.29 USD



Currency


Login

Email:

Password:

Remember Me

Forgot Your Password?

Don't Have an Account?
Sign Up!